Method of forming billets or blooms for forming tubes by extrusion.



J. W. LEIGHTON. METHOD OF FORMING BILLETS OR'BLOOMS FOR FORMING TUBES BY EXTRUSION.

APPLICATION FILED APR. 2s. 19!]. 1,310,123.

' Patented July 15, 1919.

IUED STATES FATE a WYOLIFFE LnreHron, or 'rononro; onreruo, CANADA, nssrenon T0 rnnssnn METALS, LIMITED, OF TORONTO, ONTARIO, CANADA, A. CORPORATION.

METHOD OF FORMING BILLETS OR BLOOMS FOR FORMING TUBES BY EXTRUSION.

To all whom it may concern Be it known that I, JOHN WYGLIFFE Lnren'ron, a subject of the King of Great Britain, and resident of the city of Toronto, county of York, Province of Ontario, in the Dominion of Canada, have invented certain new and useful Improvements in Methods of Forming Billets or Blooms for Forming Tu'bes by Extrusion, as described in the fol-" vention is to so treat the metal as to efi'ectively size the billet and compress the material to a uniform state and to coincidently pierce the billet.

The principal feature of the invention consists in subjecting the billet of cast metal to a uniform pressure within a confined space and extruding the surplus metal from the billet by means of cooperating punches.

In the accompanying drawings Figure 1 is a diagrammatic sectional view showing the billet placed within the die of a double acting punch press.-

Fi 2 is a sectional view through the die showing the punches in their lowermost position having effected the piercing of the billet.

Like numerals of reference indicate corresponding parts in each figure.

In the practice of formlng metal tubes by extrusion it has been found in using cast metal billets or bloom that uniform results could not be relied upon for various reasons. In some instances the texture of the metal in the bloom is not uniform, that is to say, the metal might be more porous upon one side than on the other due to formation of gas I beveled I at the edges.

in casting the bloom and in other instances the boring of a hole"through the bloom for the insertion of the formerwould not be perfectly central. These and other conditions caused inaccuracies in the extrusion process of forming the tube.

In carrying the prewnt invention into effect the cast billet 1 shown placed in the die recess 2 in Fig. 1 of the drawings is formed slightly tapered, having its smaller end 3 n he die recess 2 is formed with tapering walls and a bushing 4 Specification of Letters Patent.

' the the metal after filling the die completely to Patented July 15, 1919.

Application filed April as, 1917. semi No. 164,536.

is arranged at the bottom, said bushing having a. central openin of the same diameter as the hole which it is e'sired to pierce through the billet.

The press usedis of any ordinary double acting form having the the ram 6 adapted to fit in to the top of the die recess 2 to close the same. A central punch 7 extends through the center of the punch 5 and is adapted to be operated witha movement following that of the punch 5. The punch 5 closes the top of the die and the punch 7 passing through the die 5 is forced into the metal of the billet. The pressure exerted by the punch 7 causes the metal of the billet to flow and to first completely fill the confining walls of the die and if the billet is slightly under size the metal will flow upwardly to meet the punch 5. If the billet is slightly over size then the first pressure of punch 5.as it enters the die will cause extrude into the opening through the collar 4. The punch 7 forces the surplus metal out through the opening in the collar 4 and forms a perfectly centralized hole through the billet.

It will be readily understood that as the billets are heated and pressed in their hot .state in the manner described and as the pressure of the punch 7 is suflicient to cause the flow of the metal to form the central hole the entire texture of the metal of the billet is compressed and altered to a uniform state.

It is found in actual practice that the piece of metal extruded from the die varies in length with each billet so that the metal extruded is merely the surplus after the billet has been sized and compressed and pierced.

Billets or blooms thus formed will be, extremely uniform in all respects with the result that the very best results will be obtained in using such blooms in forming metal tubes by extrusion.

It will also be seen that the operation is extremely simple and is performed very rapidly, consequently not onlyis 'a much punch 5 secured to v greater length than the diameter of hole to be formed therein, then confining the billet Within a closed die of fixed dimensions, then forcing a punch of much lesser diameter then the length of the billet lengthwise into the metal causing it to flow as the punch is advanced thereinto and unify the density of the entire body of metal, the surplus metal being extruded through an opening at the end of the die opposite to that at which the punch for making tubes by extrusion consisting in first molding a billet of cast metal, then heating the billet, then placing it in a die, then 5 closing the open'end of the die, then forcing a punch of considerably lesser diameter than the billet into and longitudinally through the billet displacing the metal in advance of the punch laterally and effecting-the unifying of the density of the entire body of metal, the surplus metal being extruded through. an opening arranged at the end of the die opposite to that, at which the punch enters.

J. W. LEIGH'roN. 

